Mater does not have any personality in materialism since the person is the thing that experiences, decides and causes. That is true since it is believed that the person exists in only alive beings as a result of emergence. The emergence of the person is, however, contrary in materialism. Why it is contrary? Because emergence is the result of matter activities. Mind, however, should be able to change the matter activity otherwise it is irrelevant. This means that the mind should exist and exist not at the same point. The mind should exist because it is required to change matter activity. The mind should exist not in or order to emerge as a result of matter activity.
In another way, the state of mater defines the person so it cannot be affected by the person that is the emergent thing as the result of matter activity.
In another way, the specific state of mater which is the result of mater activity, the person, is unique in materialism. This state cannot change to a state that the person wishes since the person itself cannot affect the thing that is the cause of the emergence of the person.